Topic
Micromixing
About: Micromixing is a research topic. Over the lifetime, 781 publications have been published within this topic receiving 19167 citations.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: In this paper, the Damkohler number was used to correlate processing of a confined impinging jets (CIJ) mixer with a second-order competitive reaction set, and a scaling theory for the characteristic micromixing time, proportional to momentum diffusion starting at the Kolmogorov microscale, was presented.
Abstract: Rapid processes such as certain organic reactions or precipitations at high supersaturation require the rapid mixing provided by jet mixers. Micromixing in a confined impinging jets (CIJ) mixer was characterized employing the Damkohler number to correlate processing. A scaling theory for the characteristic micromixing time, proportional to momentum diffusion starting at the Kolmogorov microscale, is shown as sufficient to express the micromixing performance of the CIJ mixer. A recently characterized second-order competitive reaction set is used as a “chemical ruler” to assign an absolute value to the mixing time in the CIJ mixer. A wide range of characteristic time (320 to 5 ms) is evaluated with hydrochloric acid competing for sodium hydroxide neutralization or 2,2-dimethoxypropane acid catalyzed hydrolysis. This reaction set was sensitive enough to detect the onset of a turbulent-like flow at a Re of 90 and was able to demonstrate a decrease in undesired products up to the highest Re tested, 3,800 or a jet velocity of 19 m/s. It represents a significant advancement to the reaction sets and techniques used for previous mixing studies, which are reviewed. Experiments verify the characteristic mixing time in a CIJ mixer scales as the inverse of the jet velocity to the three halves power, and the “mesomixing volume” (the volume over which the majority of flow energy was dissipated) is best approximated as proportional to the internozzle separation cubed. For each of the different jet diameters, chamber diameters and outlet configurations tested, the selectivity of the reaction scaled linearly with the Damkohler number, as determined from the known reaction kinetics and the calculated Kolmogorov diffusion time. The first full characterization is provided of micromixing in impinging jets that allows the prediction of mixing performance, reaction selectivity, and scale-up criteria.
663 citations
Book•
24 Feb 1999
TL;DR: In this article, a Lagrangian framework is used to model mixing of non-reacting materials, from Turbulent Diffusion to Mixing on Molecular Scale, and the evaluation of mixing models is presented.
Abstract: Introduction-Mixing and Reaction. Bulk Flow Patterns and the Selectivity of Slow Reactions. Fast Reactions and the Limits of Classical Methods. The Nature and Definition of Turbulence. Theory of Turbulence and Models of Turbulent Flow. Mixing of Non-Reacting Materials: From Turbulent Diffusion to Mixing on Molecular Scale. Analysis and Modelling of Mixing of Reactive Materials. Mixing and Chemical Reaction in a Lagrangian Framework-Mechanistic Models. The Evaluation of Mixing Models: General Considerations. Mechanisms and Kinetics of Some Test Reactions. Model-Experiment Comparisons when Micromixing Controls. Model-Experiment Comparisons when Micro- and Mesomixing Control. Characteristics of Various Mixers. Precipitation. Further Applications. Index.
634 citations
TL;DR: An integrated microfluidic system that achieves efficient mixing between two miscible liquid streams by introducing a gas phase, forming a segmented gas-liquid (slug) flow, and completely separating the mixed liquid and gas streams in a planar capillary separator is presented.
Abstract: We present an integrated microfluidic system that achieves efficient mixing between two miscible liquid streams by introducing a gas phase, forming a segmented gas-liquid (slug) flow, and completely separating the mixed liquid and gas streams in a planar capillary separator. The recirculation motion associated with segmented flow enhances advection in straight microchannels without requiring additional fabrication steps. Instantaneous velocity fields are quantified by microscopic particle image velocimetry (muPIV). Velocities in the direction normal to the channel amount to approximately 30% of the bulk liquid velocity inside a liquid segment. This value depends only weakly on the length of a liquid segment. Spatial concentration fields and the extent of mixing (EOM) are obtained from pulsed-laser fluorescence microscopy and confocal scanning microscopy measurements. The mixing length is reduced 2-3-fold in comparison with previously reported chaotic micromixers that use three-dimensional microchannel networks or patterned walls. Segmented gas-liquid microflows allow mixing times to be varied over several orders of magnitude between milliseconds and second time scales.
466 citations
TL;DR: A state-of-art review on microstructured mixing devices and their mixing phenomena is given and the advantages and disadvantages of mixing in a microfluidic environment are discussed.
Abstract: Micromixing is a crucial process within microfluidic systems such as micro total analysis systems (μTAS). A state-of-art review on microstructured mixing devices and their mixing phenomena is given. The review first presents an overview of the characteristics of fluidic behavior at the microscale and their implications in microfluidic mixing processes. According to the two basic principles exploited to induce mixing at the microscale, micromixers are generally classified as being passive or active. Passive mixers solely rely on pumping energy, whereas active mixers rely on an external energy source to achieve mixing. Typical types of passive micromixers are discussed, including T- or Y-shaped, parallel lamination, sequential, focusing enhanced mixers, and droplet micromixers. Examples of active mixers using external forces such as pressure field, electrokinetic, dielectrophoretic, electrowetting, magneto-hydrodynamic, and ultrasound to assist mixing are presented. Finally, the advantages and disadvantages of mixing in a microfluidic environment are discussed.
448 citations
TL;DR: Air bubbles resting on a solid surface and set into vibration by the sound field generated steady circulatory flows, resulting in global convection flows and thus rapid mixing, and acoustic microstreaming provided efficient mixing of bacterial cell matrix suspended in blood with magnetic capture beads resulting in highly effective immunomagnetic cell capture.
Abstract: A mixing technique based on the principle of bubble-induced acoustic microstreaming was developed. The mixer consists of a piezoelectric disk that is attached to a reaction chamber, which is designed in such a way that a set of air bubbles with desirable size is trapped in the solution. Fluidic experiments showed that air bubbles resting on a solid surface and set into vibration by the sound field generated steady circulatory flows, resulting in global convection flows and thus rapid mixing. The time to fully mix a 22 μL chamber is significantly reduced from hours (for a pure diffusion-based mixing) to tens of seconds. Numerical simulations showed that the induced flowfield and thus degree of mixing strongly depend on bubble positions. Optimal simulated mixing results were obtained for staggered bubble distribution that minimizes the number of internal flow stagnation regions. Immunomagnetic cell capture experiments showed that acoustic microstreaming provided efficient mixing
of bacterial cell (Esherichia coli K12) matrix suspended in blood with magnetic capture beads, resulting in highly effective immunomagnetic cell capture. Bacterial viability assay experiments showed that acoustic microstreaming has a relatively low shear strain field since the blood cells and bacteria remained intact after mixing. Acoustic microstreaming has many advantages over most existing chamber micromixing techniques, including simple apparatus, ease of implementation, low power consumption (2 mW), and low cost.
414 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 10 |
| 2024 | 31 |
| 2023 | 46 |
| 2022 | 71 |
| 2021 | 26 |
| 2020 | 38 |